/*******************************************************************************
 * Copyright (c) 2013, 2015 EclipseSource.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 ******************************************************************************/
package io.github.jopenlibs.vault.json;

import io.github.jopenlibs.vault.json.JsonObject.Member;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;


/**
 * Represents a JSON object, a set of name/value pairs, where the names are strings and the values
 * are JSON values.
 * <p>
 * Members can be added using the <code>add(String, ...)</code> methods which accept instances of
 * {@link JsonValue}, strings, primitive numbers, and boolean values. To modify certain values of an
 * object, use the <code>set(String, ...)</code> methods. Please note that the <code>add</code>
 * methods are faster than <code>set</code> as they do not search for existing members. On the other
 * hand, the <code>add</code> methods do not prevent adding multiple members with the same name.
 * Duplicate names are discouraged but not prohibited by JSON.
 * </p>
 * <p>
 * Members can be accessed by their name using {@link #get(String)}. A list of all names can be
 * obtained from the method {@link #names()}. This class also supports iterating over the members in
 * document order using an {@link #iterator()} or an enhanced for loop:
 * </p>
 * <pre>
 * for (Member member : jsonObject) {
 *   String name = member.getName();
 *   JsonValue value = member.getValue();
 *   ...
 * }
 * </pre>
 * <p>
 * Even though JSON objects are unordered by definition, instances of this class preserve the order
 * of members to allow processing in document order and to guarantee a predictable output.
 * </p>
 * <p>
 * Note that this class is <strong>not thread-safe</strong>. If multiple threads access a
 * <code>JsonObject</code> instance concurrently, while at least one of these threads modifies the
 * contents of this object, access to the instance must be synchronized externally. Failure to do so
 * may lead to an inconsistent state.
 * </p>
 * <p>
 * This class is <strong>not supposed to be extended</strong> by clients.
 * </p>
 */
@SuppressWarnings({"serial", "PMD"}) // use default serial UID
public class JsonObject extends JsonValue implements Iterable<Member> {

    private final List<String> names;
    private final List<JsonValue> values;
    private transient HashIndexTable table;

    /**
     * Creates a new empty JsonObject.
     */
    public JsonObject() {
        names = new ArrayList<>();
        values = new ArrayList<>();
        table = new HashIndexTable();
    }

    /**
     * Creates a new JsonObject, initialized with the contents of the specified JSON object.
     *
     * @param object the JSON object to get the initial contents from, must not be
     * <code>null</code>
     */
    public JsonObject(JsonObject object) {
        this(object, false);
    }

    private JsonObject(JsonObject object, boolean unmodifiable) {
        if (object == null) {
            throw new NullPointerException("object is null");
        }
        if (unmodifiable) {
            names = Collections.unmodifiableList(object.names);
            values = Collections.unmodifiableList(object.values);
        } else {
            names = new ArrayList<>(object.names);
            values = new ArrayList<>(object.values);
        }
        table = new HashIndexTable();
        updateHashIndex();
    }

    /**
     * Returns an unmodifiable JsonObject for the specified one. This method allows to provide
     * read-only access to a JsonObject.
     * <p>
     * The returned JsonObject is backed by the given object and reflect changes that happen to it.
     * Attempts to modify the returned JsonObject result in an
     * <code>UnsupportedOperationException</code>.
     * </p>
     *
     * @param object the JsonObject for which an unmodifiable JsonObject is to be returned
     * @return an unmodifiable view of the specified JsonObject
     */
    public static JsonObject unmodifiableObject(JsonObject object) {
        return new JsonObject(object, true);
    }

    /**
     * Appends a new member to the end of this object, with the specified name and the JSON
     * representation of the specified <code>int</code> value.
     * <p>
     * This method <strong>does not prevent duplicate names</strong>. Calling this method with a
     * name that already exists in the object will append another member with the same name. In
     * order to replace existing members, use the method <code>set(name, value)</code> instead.
     * However,
     * <strong> <em>add</em> is much faster than <em>set</em></strong> (because it does not need to
     * search for existing members). Therefore <em>add</em> should be preferred when constructing
     * new objects.
     * </p>
     *
     * @param name the name of the member to add
     * @param value the value of the member to add
     * @return the object itself, to enable method chaining
     */
    public JsonObject add(String name, int value) {
        add(name, Json.value(value));
        return this;
    }

    /**
     * Appends a new member to the end of this object, with the specified name and the JSON
     * representation of the specified <code>int[]</code> value.
     * <p>
     * This method <strong>does not prevent duplicate names</strong>. Calling this method with a
     * name that already exists in the object will append another member with the same name. In
     * order to replace existing members, use the method <code>set(name, value)</code> instead.
     * However,
     * <strong> <em>add</em> is much faster than <em>set</em></strong> (because it does not need to
     * search for existing members). Therefore <em>add</em> should be preferred when constructing
     * new objects.
     * </p>
     *
     * @param name the name of the member to add
     * @param value the value of the member to add
     * @return the object itself, to enable method chaining
     */
    public JsonObject add(String name, int[] value) {
        add(name, Json.value(value));
        return this;
    }


    /**
     * Appends a new member to the end of this object, with the specified name and the JSON
     * representation of the specified <code>long</code> value.
     * <p>
     * This method <strong>does not prevent duplicate names</strong>. Calling this method with a
     * name that already exists in the object will append another member with the same name. In
     * order to replace existing members, use the method <code>set(name, value)</code> instead.
     * However,
     * <strong> <em>add</em> is much faster than <em>set</em></strong> (because it does not need to
     * search for existing members). Therefore <em>add</em> should be preferred when constructing
     * new objects.
     * </p>
     *
     * @param name the name of the member to add
     * @param value the value of the member to add
     * @return the object itself, to enable method chaining
     */
    public JsonObject add(String name, long value) {
        add(name, Json.value(value));
        return this;
    }

    /**
     * Appends a new member to the end of this object, with the specified name and the JSON
     * representation of the specified <code>float</code> value.
     * <p>
     * This method <strong>does not prevent duplicate names</strong>. Calling this method with a
     * name that already exists in the object will append another member with the same name. In
     * order to replace existing members, use the method <code>set(name, value)</code> instead.
     * However,
     * <strong> <em>add</em> is much faster than <em>set</em></strong> (because it does not need to
     * search for existing members). Therefore <em>add</em> should be preferred when constructing
     * new objects.
     * </p>
     *
     * @param name the name of the member to add
     * @param value the value of the member to add
     * @return the object itself, to enable method chaining
     */
    public JsonObject add(String name, float value) {
        add(name, Json.value(value));
        return this;
    }

    /**
     * Appends a new member to the end of this object, with the specified name and the JSON
     * representation of the specified <code>double</code> value.
     * <p>
     * This method <strong>does not prevent duplicate names</strong>. Calling this method with a
     * name that already exists in the object will append another member with the same name. In
     * order to replace existing members, use the method <code>set(name, value)</code> instead.
     * However,
     * <strong> <em>add</em> is much faster than <em>set</em></strong> (because it does not need to
     * search for existing members). Therefore <em>add</em> should be preferred when constructing
     * new objects.
     * </p>
     *
     * @param name the name of the member to add
     * @param value the value of the member to add
     * @return the object itself, to enable method chaining
     */
    public JsonObject add(String name, double value) {
        add(name, Json.value(value));
        return this;
    }

    /**
     * Appends a new member to the end of this object, with the specified name and the JSON
     * representation of the specified <code>boolean</code> value.
     * <p>
     * This method <strong>does not prevent duplicate names</strong>. Calling this method with a
     * name that already exists in the object will append another member with the same name. In
     * order to replace existing members, use the method <code>set(name, value)</code> instead.
     * However,
     * <strong> <em>add</em> is much faster than <em>set</em></strong> (because it does not need to
     * search for existing members). Therefore <em>add</em> should be preferred when constructing
     * new objects.
     * </p>
     *
     * @param name the name of the member to add
     * @param value the value of the member to add
     * @return the object itself, to enable method chaining
     */
    public JsonObject add(String name, boolean value) {
        add(name, Json.value(value));
        return this;
    }

    /**
     * Appends a new member to the end of this object, with the specified name and the JSON
     * representation of the specified string.
     * <p>
     * This method <strong>does not prevent duplicate names</strong>. Calling this method with a
     * name that already exists in the object will append another member with the same name. In
     * order to replace existing members, use the method <code>set(name, value)</code> instead.
     * However,
     * <strong> <em>add</em> is much faster than <em>set</em></strong> (because it does not need to
     * search for existing members). Therefore <em>add</em> should be preferred when constructing
     * new objects.
     * </p>
     *
     * @param name the name of the member to add
     * @param value the value of the member to add
     * @return the object itself, to enable method chaining
     */
    public JsonObject add(String name, String value) {
        add(name, Json.value(value));
        return this;
    }

    /**
     * Appends a new member to the end of this object, with the specified name and the JSON
     * representation of the specified casted Object <strong>only if the value is not
     * null</strong>.
     * <p>
     * This method <strong>does not prevent duplicate names</strong>. Calling this method with a
     * name that already exists in the object will append another member with the same name. In
     * order to replace existing members, use the method <code>set(name, value)</code> instead.
     * However,
     * <strong> <em>add</em> is much faster than <em>set</em></strong> (because it does not need to
     * search for existing members). Therefore <em>add</em> should be preferred when constructing
     * new objects.
     * </p>
     *
     * @param name the name of the member to add
     * @param value the value of the member to add
     * @return the object itself, to enable method chaining
     */
    public JsonObject addIfNotNull(final String name, final Object value) {
        if (value == null) {
            return this;
        }
        if (value instanceof JsonValue) {
            this.add(name, (JsonValue) value);
        } else if (value instanceof Integer) {
            this.add(name, (Integer) value);
        } else if (value instanceof Long) {
            this.add(name, (Long) value);
        } else if (value instanceof Float) {
            this.add(name, (Float) value);
        } else if (value instanceof Double) {
            this.add(name, (Double) value);
        } else if (value instanceof Boolean) {
            this.add(name, (Boolean) value);
        } else if (value instanceof String) {
            this.add(name, (String) value);
        }
        return this;
    }

    /**
     * Appends a new member to the end of this object, with the specified name and the specified
     * JSON value.
     * <p>
     * This method <strong>does not prevent duplicate names</strong>. Calling this method with a
     * name that already exists in the object will append another member with the same name. In
     * order to replace existing members, use the method <code>set(name, value)</code> instead.
     * However,
     * <strong> <em>add</em> is much faster than <em>set</em></strong> (because it does not need to
     * search for existing members). Therefore <em>add</em> should be preferred when constructing
     * new objects.
     * </p>
     *
     * @param name the name of the member to add
     * @param value the value of the member to add, must not be <code>null</code>
     * @return the object itself, to enable method chaining
     */
    public JsonObject add(String name, JsonValue value) {
        if (name == null) {
            throw new NullPointerException("name is null");
        }
        if (value == null) {
            throw new NullPointerException("value is null");
        }
        table.add(name, names.size());
        names.add(name);
        values.add(value);
        return this;
    }

    /**
     * Sets the value of the member with the specified name to the JSON representation of the
     * specified <code>int</code> value. If this object does not contain a member with this name, a
     * new member is added at the end of the object. If this object contains multiple members with
     * this name, only the last one is changed.
     * <p>
     * This method should <strong>only be used to modify existing objects</strong>. To fill a new
     * object with members, the method <code>add(name, value)</code> should be preferred which is
     * much faster (as it does not need to search for existing members).
     * </p>
     *
     * @param name the name of the member to replace
     * @param value the value to set to the member
     * @return the object itself, to enable method chaining
     */
    public JsonObject set(String name, int value) {
        set(name, Json.value(value));
        return this;
    }

    /**
     * Sets the value of the member with the specified name to the JSON representation of the
     * specified <code>long</code> value. If this object does not contain a member with this name, a
     * new member is added at the end of the object. If this object contains multiple members with
     * this name, only the last one is changed.
     * <p>
     * This method should <strong>only be used to modify existing objects</strong>. To fill a new
     * object with members, the method <code>add(name, value)</code> should be preferred which is
     * much faster (as it does not need to search for existing members).
     * </p>
     *
     * @param name the name of the member to replace
     * @param value the value to set to the member
     * @return the object itself, to enable method chaining
     */
    public JsonObject set(String name, long value) {
        set(name, Json.value(value));
        return this;
    }

    /**
     * Sets the value of the member with the specified name to the JSON representation of the
     * specified <code>float</code> value. If this object does not contain a member with this name,
     * a new member is added at the end of the object. If this object contains multiple members with
     * this name, only the last one is changed.
     * <p>
     * This method should <strong>only be used to modify existing objects</strong>. To fill a new
     * object with members, the method <code>add(name, value)</code> should be preferred which is
     * much faster (as it does not need to search for existing members).
     * </p>
     *
     * @param name the name of the member to add
     * @param value the value of the member to add
     * @return the object itself, to enable method chaining
     */
    public JsonObject set(String name, float value) {
        set(name, Json.value(value));
        return this;
    }

    /**
     * Sets the value of the member with the specified name to the JSON representation of the
     * specified <code>double</code> value. If this object does not contain a member with this name,
     * a new member is added at the end of the object. If this object contains multiple members with
     * this name, only the last one is changed.
     * <p>
     * This method should <strong>only be used to modify existing objects</strong>. To fill a new
     * object with members, the method <code>add(name, value)</code> should be preferred which is
     * much faster (as it does not need to search for existing members).
     * </p>
     *
     * @param name the name of the member to add
     * @param value the value of the member to add
     * @return the object itself, to enable method chaining
     */
    public JsonObject set(String name, double value) {
        set(name, Json.value(value));
        return this;
    }

    /**
     * Sets the value of the member with the specified name to the JSON representation of the
     * specified <code>boolean</code> value. If this object does not contain a member with this
     * name, a new member is added at the end of the object. If this object contains multiple
     * members with this name, only the last one is changed.
     * <p>
     * This method should <strong>only be used to modify existing objects</strong>. To fill a new
     * object with members, the method <code>add(name, value)</code> should be preferred which is
     * much faster (as it does not need to search for existing members).
     * </p>
     *
     * @param name the name of the member to add
     * @param value the value of the member to add
     * @return the object itself, to enable method chaining
     */
    public JsonObject set(String name, boolean value) {
        set(name, Json.value(value));
        return this;
    }

    /**
     * Sets the value of the member with the specified name to the JSON representation of the
     * specified string. If this object does not contain a member with this name, a new member is
     * added at the end of the object. If this object contains multiple members with this name, only
     * the last one is changed.
     * <p>
     * This method should <strong>only be used to modify existing objects</strong>. To fill a new
     * object with members, the method <code>add(name, value)</code> should be preferred which is
     * much faster (as it does not need to search for existing members).
     * </p>
     *
     * @param name the name of the member to add
     * @param value the value of the member to add
     * @return the object itself, to enable method chaining
     */
    public JsonObject set(String name, String value) {
        set(name, Json.value(value));
        return this;
    }

    /**
     * Sets the value of the member with the specified name to the specified JSON value. If this
     * object does not contain a member with this name, a new member is added at the end of the
     * object. If this object contains multiple members with this name, only the last one is
     * changed.
     * <p>
     * This method should <strong>only be used to modify existing objects</strong>. To fill a new
     * object with members, the method <code>add(name, value)</code> should be preferred which is
     * much faster (as it does not need to search for existing members).
     * </p>
     *
     * @param name the name of the member to add
     * @param value the value of the member to add, must not be <code>null</code>
     * @return the object itself, to enable method chaining
     */
    public JsonObject set(String name, JsonValue value) {
        if (name == null) {
            throw new NullPointerException("name is null");
        }
        if (value == null) {
            throw new NullPointerException("value is null");
        }
        int index = indexOf(name);
        if (index != -1) {
            values.set(index, value);
        } else {
            table.add(name, names.size());
            names.add(name);
            values.add(value);
        }
        return this;
    }

    /**
     * Removes a member with the specified name from this object. If this object contains multiple
     * members with the given name, only the last one is removed. If this object does not contain a
     * member with the specified name, the object is not modified.
     *
     * @param name the name of the member to remove
     * @return the object itself, to enable method chaining
     */
    public JsonObject remove(String name) {
        if (name == null) {
            throw new NullPointerException("name is null");
        }
        int index = indexOf(name);
        if (index != -1) {
            table.remove(index);
            names.remove(index);
            values.remove(index);
        }
        return this;
    }

    /**
     * Copies all members of the specified object into this object. When the specified object
     * contains members with names that also exist in this object, the existing values in this
     * object will be replaced by the corresponding values in the specified object.
     *
     * @param object the object to merge
     * @return the object itself, to enable method chaining
     */
    public JsonObject merge(JsonObject object) {
        if (object == null) {
            throw new NullPointerException("object is null");
        }
        for (Member member : object) {
            this.set(member.name, member.value);
        }
        return this;
    }

    /**
     * Returns the value of the member with the specified name in this object. If this object
     * contains multiple members with the given name, this method will return the last one.
     *
     * @param name the name of the member whose value is to be returned
     * @return the value of the last member with the specified name, or <code>null</code> if this
     * object does not contain a member with that name
     */
    public JsonValue get(String name) {
        if (name == null) {
            throw new NullPointerException("name is null");
        }
        int index = indexOf(name);
        return index != -1 ? values.get(index) : null;
    }

    /**
     * Returns the <code>Integer</code> value of the member with the specified name in this object.
     * If this object does not contain a member with this name, <strong><code>null</code></strong>
     * is returned. If this object contains multiple members with the given name, the last one will
     * be picked. If this member's value does not represent a JSON number or if it cannot be
     * interpreted as Java
     * <code>int</code>, an exception is thrown.
     *
     * @param name the name of the member whose value is to be returned
     * @return the value of the last member with the specified name, or null if this object does not
     * contain a member with that name
     */
    public Integer getInt(String name) {
        JsonValue value = get(name);
        return value != null ? value.asInt() : null;
    }

    /**
     * Returns the <code>int</code> value of the member with the specified name in this object. If
     * this object does not contain a member with this name, the given default value is returned. If
     * this object contains multiple members with the given name, the last one will be picked. If
     * this member's value does not represent a JSON number or if it cannot be interpreted as Java
     * <code>int</code>, an exception is thrown.
     *
     * @param name the name of the member whose value is to be returned
     * @param defaultValue the value to be returned if the requested member is missing
     * @return the value of the last member with the specified name, or the given default value if
     * this object does not contain a member with that name
     */
    public int getInt(String name, int defaultValue) {
        JsonValue value = get(name);
        return value != null ? value.asInt() : defaultValue;
    }

    /**
     * Returns the <code>Long</code> value of the member with the specified name in this object. If
     * this object does not contain a member with this name, <strong><code>null</code></strong> is
     * returned. If this object contains multiple members with the given name, the last one will be
     * picked. If this member's value does not represent a JSON number or if it cannot be
     * interpreted as Java
     * <code>long</code>, an exception is thrown.
     *
     * @param name the name of the member whose value is to be returned
     * @return the value of the last member with the specified name, or null if this object does not
     * contain a member with that name
     */
    public Long getLong(String name) {
        JsonValue value = get(name);
        return value != null ? value.asLong() : null;
    }

    /**
     * Returns the <code>long</code> value of the member with the specified name in this object. If
     * this object does not contain a member with this name, the given default value is returned. If
     * this object contains multiple members with the given name, the last one will be picked. If
     * this member's value does not represent a JSON number or if it cannot be interpreted as Java
     * <code>long</code>, an exception is thrown.
     *
     * @param name the name of the member whose value is to be returned
     * @param defaultValue the value to be returned if the requested member is missing
     * @return the value of the last member with the specified name, or the given default value if
     * this object does not contain a member with that name
     */
    public long getLong(String name, long defaultValue) {
        JsonValue value = get(name);
        return value != null ? value.asLong() : defaultValue;
    }

    /**
     * Returns the <code>Float</code> value of the member with the specified name in this object. If
     * this object does not contain a member with this name, <strong><code>null</code></strong> is
     * returned. If this object contains multiple members with the given name, the last one will be
     * picked. If this member's value does not represent a JSON number or if it cannot be
     * interpreted as Java
     * <code>float</code>, an exception is thrown.
     *
     * @param name the name of the member whose value is to be returned
     * @return the value of the last member with the specified name, or null if this object does not
     * contain a member with that name
     */
    public Float getFloat(String name) {
        JsonValue value = get(name);
        return value != null ? value.asFloat() : null;
    }

    /**
     * Returns the <code>float</code> value of the member with the specified name in this object. If
     * this object does not contain a member with this name, the given default value is returned. If
     * this object contains multiple members with the given name, the last one will be picked. If
     * this member's value does not represent a JSON number or if it cannot be interpreted as Java
     * <code>float</code>, an exception is thrown.
     *
     * @param name the name of the member whose value is to be returned
     * @param defaultValue the value to be returned if the requested member is missing
     * @return the value of the last member with the specified name, or the given default value if
     * this object does not contain a member with that name
     */
    public float getFloat(String name, float defaultValue) {
        JsonValue value = get(name);
        return value != null ? value.asFloat() : defaultValue;
    }

    /**
     * Returns the <code>Double</code> value of the member with the specified name in this object.
     * If this object does not contain a member with this name, <strong><code>null</code></strong>
     * is returned. If this object contains multiple members with the given name, the last one will
     * be picked. If this member's value does not represent a JSON number or if it cannot be
     * interpreted as Java
     * <code>double</code>, an exception is thrown.
     *
     * @param name the name of the member whose value is to be returned
     * @return the value of the last member with the specified name, or null if this object does not
     * contain a member with that name
     */
    public Double getDouble(String name) {
        JsonValue value = get(name);
        return value != null ? value.asDouble() : null;
    }

    /**
     * Returns the <code>double</code> value of the member with the specified name in this object.
     * If this object does not contain a member with this name, the given default value is returned.
     * If this object contains multiple members with the given name, the last one will be picked. If
     * this member's value does not represent a JSON number or if it cannot be interpreted as Java
     * <code>double</code>, an exception is thrown.
     *
     * @param name the name of the member whose value is to be returned
     * @param defaultValue the value to be returned if the requested member is missing
     * @return the value of the last member with the specified name, or the given default value if
     * this object does not contain a member with that name
     */
    public double getDouble(String name, double defaultValue) {
        JsonValue value = get(name);
        return value != null ? value.asDouble() : defaultValue;
    }

    /**
     * Returns the <code>Boolean</code> value of the member with the specified name in this object.
     * If this object does not contain a member with this name, <strong><code>null</code></strong>
     * is returned. If this object contains multiple members with the given name, the last one will
     * be picked. If this member's value does not represent a JSON <code>true</code> or
     * <code>false</code> value, an exception is thrown.
     *
     * @param name the name of the member whose value is to be returned
     * @return the value of the last member with the specified name, or null if this object does not
     * contain a member with that name
     */
    public Boolean getBoolean(String name) {
        JsonValue value = get(name);
        return value != null ? value.asBoolean() : null;
    }

    /**
     * Returns the <code>boolean</code> value of the member with the specified name in this object.
     * If this object does not contain a member with this name, the given default value is returned.
     * If this object contains multiple members with the given name, the last one will be picked. If
     * this member's value does not represent a JSON <code>true</code> or <code>false</code> value,
     * an exception is thrown.
     *
     * @param name the name of the member whose value is to be returned
     * @param defaultValue the value to be returned if the requested member is missing
     * @return the value of the last member with the specified name, or the given default value if
     * this object does not contain a member with that name
     */
    public boolean getBoolean(String name, boolean defaultValue) {
        JsonValue value = get(name);
        return value != null ? value.asBoolean() : defaultValue;
    }

    /**
     * Returns the <code>String</code> value of the member with the specified name in this object.
     * If this object does not contain a member with this name, <strong><code>null</code></strong>
     * is returned. If this object contains multiple members with the given name, the last one is
     * picked. If this member's value does not represent a JSON string, an exception is thrown.
     *
     * @param name the name of the member whose value is to be returned
     * @return the value of the last member with the specified name, or null if this object does not
     * contain a member with that name
     */
    public String getString(String name) {
        JsonValue value = get(name);
        return value != null ? value.asString() : null;
    }

    /**
     * Returns the <code>String</code> value of the member with the specified name in this object.
     * If this object does not contain a member with this name, the given default value is returned.
     * If this object contains multiple members with the given name, the last one is picked. If this
     * member's value does not represent a JSON string, an exception is thrown.
     *
     * @param name the name of the member whose value is to be returned
     * @param defaultValue the value to be returned if the requested member is missing
     * @return the value of the last member with the specified name, or the given default value if
     * this object does not contain a member with that name
     */
    public String getString(String name, String defaultValue) {
        JsonValue value = get(name);
        return value != null ? value.asString() : defaultValue;
    }

    /**
     * Returns the number of members (name/value pairs) in this object.
     *
     * @return the number of members in this object
     */
    public int size() {
        return names.size();
    }

    /**
     * Returns <code>true</code> if this object contains no members.
     *
     * @return <code>true</code> if this object contains no members
     */
    public boolean isEmpty() {
        return names.isEmpty();
    }

    /**
     * Returns a list of the names in this object in document order. The returned list is backed by
     * this object and will reflect subsequent changes. It cannot be used to modify this object.
     * Attempts to modify the returned list will result in an exception.
     *
     * @return a list of the names in this object
     */
    public List<String> names() {
        return Collections.unmodifiableList(names);
    }

    /**
     * Returns an iterator over the members of this object in document order. The returned iterator
     * cannot be used to modify this object.
     *
     * @return an iterator over the members of this object
     */
    public Iterator<Member> iterator() {
        final Iterator<String> namesIterator = names.iterator();
        final Iterator<JsonValue> valuesIterator = values.iterator();
        return new Iterator<JsonObject.Member>() {

            public boolean hasNext() {
                return namesIterator.hasNext();
            }

            public Member next() {
                String name = namesIterator.next();
                JsonValue value = valuesIterator.next();
                return new Member(name, value);
            }

            public void remove() {
                throw new UnsupportedOperationException();
            }

        };
    }

    @Override
    void write(JsonWriter writer) throws IOException {
        writer.writeObjectOpen();
        Iterator<String> namesIterator = names.iterator();
        Iterator<JsonValue> valuesIterator = values.iterator();
        boolean first = true;
        while (namesIterator.hasNext()) {
            if (!first) {
                writer.writeObjectSeparator();
            }
            writer.writeMemberName(namesIterator.next());
            writer.writeMemberSeparator();
            valuesIterator.next().write(writer);
            first = false;
        }
        writer.writeObjectClose();
    }

    @Override
    public boolean isObject() {
        return true;
    }

    @Override
    public JsonObject asObject() {
        return this;
    }

    @Override
    public int hashCode() {
        int result = 1;
        result = 31 * result + names.hashCode();
        result = 31 * result + values.hashCode();
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (getClass() != obj.getClass()) {
            return false;
        }
        JsonObject other = (JsonObject) obj;
        return names.equals(other.names) && values.equals(other.values);
    }

    int indexOf(String name) {
        int index = table.get(name);
        if (index != -1 && name.equals(names.get(index))) {
            return index;
        }
        return names.lastIndexOf(name);
    }

    private synchronized void readObject(ObjectInputStream inputStream)
            throws IOException, ClassNotFoundException {
        inputStream.defaultReadObject();
        table = new HashIndexTable();
        updateHashIndex();
    }

    private void updateHashIndex() {
        int size = names.size();
        for (int i = 0; i < size; i++) {
            table.add(names.get(i), i);
        }
    }

    /**
     * Represents a member of a JSON object, a pair of a name and a value.
     */
    public static class Member {

        private final String name;
        private final JsonValue value;

        Member(String name, JsonValue value) {
            this.name = name;
            this.value = value;
        }

        /**
         * Returns the name of this member.
         *
         * @return the name of this member, never <code>null</code>
         */
        public String getName() {
            return name;
        }

        /**
         * Returns the value of this member.
         *
         * @return the value of this member, never <code>null</code>
         */
        public JsonValue getValue() {
            return value;
        }

        @Override
        public int hashCode() {
            int result = 1;
            result = 31 * result + name.hashCode();
            result = 31 * result + value.hashCode();
            return result;
        }

        @Override
        public boolean equals(Object obj) {
            if (this == obj) {
                return true;
            }
            if (obj == null) {
                return false;
            }
            if (getClass() != obj.getClass()) {
                return false;
            }
            Member other = (Member) obj;
            return name.equals(other.name) && value.equals(other.value);
        }

    }

    static class HashIndexTable {

        private final byte[] hashTable = new byte[32]; // must be a power of two

        public HashIndexTable() {
        }

        public HashIndexTable(HashIndexTable original) {
            System.arraycopy(original.hashTable, 0, hashTable, 0, hashTable.length);
        }

        void add(String name, int index) {
            int slot = hashSlotFor(name);
            if (index < 0xff) {
                // increment by 1, 0 stands for empty
                hashTable[slot] = (byte) (index + 1);
            } else {
                hashTable[slot] = 0;
            }
        }

        void remove(int index) {
            for (int i = 0; i < hashTable.length; i++) {
                if (hashTable[i] == index + 1) {
                    hashTable[i] = 0;
                } else if (hashTable[i] > index + 1) {
                    hashTable[i]--;
                }
            }
        }

        int get(Object name) {
            int slot = hashSlotFor(name);
            // subtract 1, 0 stands for empty
            return (hashTable[slot] & 0xff) - 1;
        }

        private int hashSlotFor(Object element) {
            return element.hashCode() & hashTable.length - 1;
        }

    }

}
